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| Representativeness and the CFEV projectRepresentativeness (R) is the degree to which each spatial unit is representative of a biological or physical class to which it belongs. It was assessed through a set of statewide biological and physical classifications of each ecosystem based on a range of different classification components (e.g. fish, riparian vegetation, hydrology, etc.).
Each classification covers a number of different classes, and these can be anything from widespread (like Hydrological region 3 used for Rivers which covers most of western Tasmania) to rare (like the Physical class used for waterbodies which separates out Perched lake as being a unique member of its own class).
If we consider these examples further, the latter two lakes are both highly representative of their classes and extremely rare. In contrast the 33 most representative river sections for Hydrological region 3 were decided upon using attributes such as length and condition and could easily be replaced by examples from elsewhere in western Tasmania. All of these highly representative physical units belong within the upper band (band A) of Representative Conservation Value (RCV).
Two different biophysical classes: Perched Lake is a unique member of a rare physical class, while the red river sections in central Tasmania are the most representative examples of the extensive class called Hydrological Region 3 (in blue)
Every physical unit considered by CFEV (e.g. river sections or wetlands) belongs to one class from each of the classifications that were used for that type of ecosystem. For example a river section will have 7 different classifications and it will vary in how good a representative it is of each of these, a wetland will belong to 6 different biological or physical classes. The RCV of the physical unit is driven by the class of which it is most representative.
For example, Perched Lake is the only member of its particular physical class (Wb19) making it RCV A, but Waterbodies have six different classifications to which they belong, so perched lake is also a member 5 other biological or physical classes (see table below).
| Classification | class code | class description | | Crayfish region | C2 | Astacopsis tricomis present | | Frog assemblage | FR9 | West - Assemblage characterised by high probability of occurrence of: Limnodynastes dumerili insularis, Litoria ewingi, Litoria burrowsae, Crinia signifera, Crinia tasmaniensis | | Native fish assemblage | F16 | Assemblage distributed within coastal streams and waterbodies that extend along most of the west coast including King Island through to the western edge of the Derwent River. Species Composition: Anguilla australis, Galaxias truttaceus, Geotria australis & Mordacia mordax, Prototroctes maraena, Neochanna cleaveri, Pseudaphritis urvillii, Galaxias brevipinnis, Galaxias maculatus, Retropinna tasmanica | | Tree assemblage | T43 | Western lowland riverine rainforest, tea tree forest and wet eucalypt forest . Similar communities to 21, 38 and 50. Found along the Gordon river and its tributaries: the Franklin, Maxwell, Denison and Olga rivers, extending also to the Hardwood River. Species Composition: Anodopetalum biglandulosum, Atherosperma moschatum, Cenarrhenes nitida, Eucalyptus nitida, Eucryphia lucida, Lagarostrobos franklinii, Leptospermum nitidum, Leptospermum scoparium eximium, Leptospermum scoparium var., Melaleuca squarrosa, Monotoca glauca, Nothofagus cunninghamii, Phebalium squameum, Phyllocladus aspleniifolius, Pittosporum bicolor, Tasmannia lanceolata | | Tyler class | TY9 | Lakes with natural meromictic state (only in Lower Gordon). Red-window optical environment (’fulvic dominated’). Marked stratification, with fresh epilimnion and saline to brackish hypolimnion. | | Waterbody Physical Class | Wb19 | Lowland, warm monomictic lake in SW Tasmania (Perched Lake only) |
All of these classes are far less rare than the physical class Wb19, and so this the Waterbody physical class is the Important biophysical class for Perched Lake.
The different biological and physical classifications for each of the different ecosystems are detailed in the CFEV assessment framework summary.
Descriptions of the different biophysical classes are included in the reports produced by the WIST and CFEVCI, or can be found in the CFEV technical report.
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